1. Technical Field
The present disclosure relates to cycling methods for sulfur composite lithium ion batteries.
2. Description of Related Art
The sulfur composite cathode active materials have great potential for high-performance lithium ion batteries due to their large specific capacity, abundant resources and low cost.
Unlike conventional cathode active materials, such as lithium transition metal oxides, the volumes of the cathode electrodes using the sulfur composites are likely to expand and shrink during the cycling of lithium ion batteries. It was found that the sulfur composite cathode electrodes expanded when discharging and shrank when recharging. The volume change during cycling makes the lithium ion batteries unstable. Due to the volume change, the sulfur composites in the cathode electrodes may be detached from the conducting agents and lose electrical activity. Accordingly, the capacity of the lithium ion batteries may decrease greatly with the cycling times. This causes a low capacity retention and coulombic efficiency of the sulfur composite lithium ion batteries.
What is needed, therefore, is to provide a method for cycling a sulfur composite lithium ion battery to suppress the volume change, which increases the coulombic efficiency and capacity retention of the lithium ion battery.